Steel manufacture.



UNITED srA'rns PATENT OFFICE.

JESSE M. DARKE, OF LYNN, MASSACHUSETTS, .ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

STEEL manuracrunn.

Specification of Letters Patent.

Patented Aug.16, 1910.

,No Drawing. Original application filed April 27, 1907, Serial No. 370,575. Divided and this application filed March 30, 1908. Serial No. 424,054.

To all whom it may concern:

Be it known that I, JESSE M. DARKE, a citizen of the United States, residing at Lynn, county of Essex, State of Massachusetts,'have invented certain new and useful Improvements in Steel Manufacture, of which the following is a specification.

My present application is directed to a novel process of compounding alloys, and is I a div1s1on of my application Serial No. 370,575, filed by me April- 27, 1907 and dc-- scribing a steel characterized in its chemical composition by the presence of tungsten in the ercentage now found in the so-called high speed steels, by the'presence of manganese 1n relatively high percentage, by the low carbon content, and-by the relatively low chromium content, also, in certain cases,

by the presence of vanadium in small percentage.

As a basis for the steel, Iprefer to use Swedish muck-bar, ferro-tungsten and ferrochromium. The ferro-tungsten may be of the variety now being produced by the electric furnace process and may contain about 67% tungsten and little or no carbon. The ferro-chromium may-also be of the electric furnace variety, low in carbon and contain ing say 68% chromium. I prefer to use sufficlent ferro-tungsten to give the finished steel about 13.5 per cent. tungsten, though .the percentage of tungsten may be varied a slag which floats on thetop and protects the steel. If for any reasonthe components are too dry to produce slag, I add a certain amount of slag to the crucible according to common practice. When the steel is nearly ready for pouring, I introduce sufficient manganese to yield a finished steel having approximately 3% manganese. Some variation in the manganese content is permissible, but the quantity should not be greater than 3.25% nor less than 2%. I prefer to introduce this manganese as pure metal, or at least in a form substantially or entirely free from carbon. The manganese now commercially produced by the Goldschmidt thermit process is substantially free from carbon and is quite suitable for use accordin to my invention.

As t e protective layer of slag in the cru cible has a great chemical aflinity for manganese, speclal means must be resorted to for introduclng the manganese into the'steel. I find that this step can be successfully effected by introducing a tube of iron, steel or other suitable material through the top of the furnace and into the crucible until the end of the tube is 'well below the layer of slag, and then introducing the manganese through the tube. The manganese may be in lumps the size of a walnut and will pass through the tube into the steel with very little loss by slagging. After the manganese is introduced, ,the crucible may remain in the fire for about five minutes and may then be poured in the usual way.

The steel resulting from the above described process may be hardened like other air hardening steels and is suitable for cutting tools. Like the alloy steels relatively high in chromium, it may be used fonheavy cuts at high speed. The tools retain their cutting edge at high temperatures much better than carbon steels, and are in other ways.

well suited for heavy duty.

For certain. pur oses I may introduce a certain quantity 0 vanadium into the steel, say in the proportion of about one-fourth of one percent. This vanadium increases the red hardness and enables the tool to stand up better when taking a heavy cut or chip; what is more important, it prevents the chip from sticking to the point of the tool. The vanadium may be introduced in any suitable form, as by including ferro-vanadium with the Swedish muck-bar and other components of the original charge.

. It will be understood that the process herein described and claimed is applicable to alloysof many different kinds and is not limited to the specific alloy referred to herein as admitting of an advantageous use of the method claimed;

What I claim as new and desire to secure by Letters Patent of the United States, is

l. The process of compounding a steel,

3. The method of compounding an alloy steel, which consists in melting some of the components, adding material to form a protective layer of slag, and subsequently introducing through a tube projecting below the layer of slag a metal having high chemical afiinity for the slag.

In Witness whereof, I have hereunto set my hand this twenty-fifth day of March, 1908.

JESSE M. DARKE.

Witnesses:

ALEX. F. MACDONALD, v JOHN A. McMAnns, Jr. 

